package com.gitee.wsl.text.reader

import com.gitee.wsl.ext.string.codePointAt
import com.gitee.wsl.lang.character.charCount
import kotlin.jvm.JvmOverloads

/**
 * The string tokenizer class allows an application to break a
 * string into tokens. The tokenization method is much simpler than
 * the one used by the `StreamTokenizer` class. The
 * `StringTokenizer` methods do not distinguish among
 * identifiers, numbers, and quoted strings, nor do they recognize
 * and skip comments.
 *
 *
 * The set of delimiters (the characters that separate tokens) may
 * be specified either at creation time or on a per-token basis.
 *
 *
 * An instance of `StringTokenizer` behaves in one of two
 * ways, depending on whether it was created with the
 * `returnDelims` flag having the value `true`
 * or `false`:
 *
 *  * If the flag is `false`, delimiter characters serve to
 * separate tokens. A token is a maximal sequence of consecutive
 * characters that are not delimiters.
 *  * If the flag is `true`, delimiter characters are themselves
 * considered to be tokens. A token is thus either one delimiter
 * character, or a maximal sequence of consecutive characters that are
 * not delimiters.
 *
 *
 * A `StringTokenizer` object internally maintains a current
 * position within the string to be tokenized. Some operations advance this
 * current position past the characters processed.
 *
 *
 * A token is returned by taking a substring of the string that was used to
 * create the `StringTokenizer` object.
 *
 *
 * The following is one example of the use of the tokenizer. The code:
 * <blockquote><pre>
 * StringTokenizer st = new StringTokenizer("this is a test");
 * while (st.hasMoreTokens()) {
 * System.out.println(st.nextToken());
 * }
</pre></blockquote> *
 *
 *
 * prints the following output:
 * <blockquote><pre>
 * this
 * is
 * a
 * test
</pre></blockquote> *
 *
 *
 *
 * `StringTokenizer` is a legacy class that is retained for
 * compatibility reasons although its use is discouraged in new code. It is
 * recommended that anyone seeking this functionality use the `split`
 * method of `String` or the java.util.regex package instead.
 *
 *
 * The following example illustrates how the `String.split`
 * method can be used to break up a string into its basic tokens:
 * <blockquote><pre>
 * String[] result = "this is a test".split("\\s");
 * for (String r : result)
 * System.out.println(r);
</pre></blockquote> *
 *
 *
 * prints the following output:
 * <blockquote><pre>
 * this
 * is
 * a
 * test
</pre></blockquote> *
 *
 * @see java.io.StreamTokenizer
 *
 * @since   1.0
 */
class StringTokenizer @JvmOverloads constructor(
    private val str: String,
    private var delimiters: String? = " \t\n\r\u000c",
    private val retDelims: Boolean = false,
) {
    private var currentPosition = 0
    private var newPosition: Int
    private val maxPosition: Int
    private var delimsChanged = false

    /**
     * maxDelimCodePoint stores the value of the delimiter character with the
     * highest value. It is used to optimize the detection of delimiter
     * characters.
     *
     * It is unlikely to provide any optimization benefit in the
     * hasSurrogates case because most string characters will be
     * smaller than the limit, but we keep it so that the two code
     * paths remain similar.
     */
    private var maxDelimCodePoint = 0

    /**
     * If delimiters include any surrogates (including surrogate
     * pairs), hasSurrogates is true and the tokenizer uses the
     * different code path. This is because String.indexOf(int)
     * doesn't handle unpaired surrogates as a single character.
     */
    private var hasSurrogates = false

    /**
     * When hasSurrogates is true, delimiters are converted to code
     * points and isDelimiter(int) is used to determine if the given
     * codepoint is a delimiter.
     */
    private lateinit var delimiterCodePoints: IntArray

    /**
     * Set maxDelimCodePoint to the highest char in the delimiter set.
     */
    private fun setMaxDelimCodePoint() {
        if (delimiters == null) {
            maxDelimCodePoint = 0
            return
        }

        var m = 0
        var c: Int
        var count = 0
        var i = 0
        while (i < delimiters!!.length) {
            c = delimiters!![i].code
            if (c >= Char.MAX_HIGH_SURROGATE/*java.lang.Character.MIN_HIGH_SURROGATE*/.code && c <= Char.MAX_LOW_SURROGATE/*java.lang.Character.MAX_LOW_SURROGATE*/.code) {
                c = delimiters!!.codePointAt(i)
                hasSurrogates = true
            }
            if (m < c) m = c
            count++
            i += c.charCount()//java.lang.Character.charCount(c)
        }
        maxDelimCodePoint = m

        if (hasSurrogates) {
            delimiterCodePoints = IntArray(count)
            var i = 0
            var j = 0
            while (i < count) {
                c = delimiters!!.codePointAt(j)
                delimiterCodePoints[i] = c
                i++
                j += c.charCount()//java.lang.Character.charCount(c)
            }
        }
    }

    /**
     * Constructs a string tokenizer for the specified string. All
     * characters in the `delim` argument are the delimiters
     * for separating tokens.
     *
     *
     * If the `returnDelims` flag is `true`, then
     * the delimiter characters are also returned as tokens. Each
     * delimiter is returned as a string consisting of a single
     * [Unicode code point](../lang/Character.html#unicode)
     * of the delimiter (which may be one or two `char`s). If the
     * flag is `false`, the delimiter characters are skipped
     * and only serve as separators between tokens.
     *
     *
     * Note that if `delim` is `null`, this constructor does
     * not throw an exception. However, trying to invoke other methods on the
     * resulting `StringTokenizer` may result in a
     * `NullPointerException`.
     *
     * @param   str            a string to be parsed.
     * @param   delimiters          the delimiters.
     * @param   retDelims   flag indicating whether to return the delimiters
     * as tokens.
     * @throws    NullPointerException if str is `null`
     */
    /**
     * Constructs a string tokenizer for the specified string. The
     * tokenizer uses the default delimiter set, which is
     * `"&nbsp;&#92;t&#92;n&#92;r&#92;f"`: the space character,
     * the tab character, the newline character, the carriage-return character,
     * and the form-feed character. Delimiter characters themselves will
     * not be treated as tokens.
     *
     * @param   str   a string to be parsed.
     * @throws    NullPointerException if str is `null`
     */
    /**
     * Constructs a string tokenizer for the specified string. The
     * characters in the `delim` argument are the delimiters
     * for separating tokens. Delimiter characters themselves will not
     * be treated as tokens.
     *
     *
     * Note that if `delim` is `null`, this constructor does
     * not throw an exception. However, trying to invoke other methods on the
     * resulting `StringTokenizer` may result in a
     * `NullPointerException`.
     *
     * @param   str     a string to be parsed.
     * @param   delim   the delimiters.
     * @throws    NullPointerException if str is `null`
     */
    init {
        newPosition = -1
        maxPosition = str.length
        setMaxDelimCodePoint()
    }

    /**
     * Skips delimiters starting from the specified position. If retDelims
     * is false, returns the index of the first non-delimiter character at or
     * after startPos. If retDelims is true, startPos is returned.
     */
    private fun skipDelimiters(startPos: Int): Int {
        if (delimiters == null) throw NullPointerException()

        var position = startPos
        while (!retDelims && position < maxPosition) {
            if (!hasSurrogates) {
                val c = str[position]
                if ((c.code > maxDelimCodePoint) || (delimiters!!.indexOf(c) < 0)) break
                position++
            } else {
                val c: Int = str.codePointAt(position)
                if ((c > maxDelimCodePoint) || !isDelimiter(c)) {
                    break
                }
                position += c.charCount()//java.lang.Character.charCount(c)
            }
        }
        return position
    }

    /**
     * Skips ahead from startPos and returns the index of the next delimiter
     * character encountered, or maxPosition if no such delimiter is found.
     */
    private fun scanToken(startPos: Int): Int {
        var position = startPos
        while (position < maxPosition) {
            if (!hasSurrogates) {
                val c = str[position]
                if ((c.code <= maxDelimCodePoint) && (delimiters!!.indexOf(c) >= 0)) break
                position++
            } else {
                val c: Int = str.codePointAt(position)
                if ((c <= maxDelimCodePoint) && isDelimiter(c)) break
                position += c.charCount()//java.lang.Character.charCount(c)
            }
        }
        if (retDelims && (startPos == position)) {
            if (!hasSurrogates) {
                val c = str[position]
                if ((c.code <= maxDelimCodePoint) && (delimiters!!.indexOf(c) >= 0)) position++
            } else {
                val c: Int = str.codePointAt(position)
                if ((c <= maxDelimCodePoint) && isDelimiter(c))
                    position += c.charCount()//java.lang.Character.charCount( c )
            }
        }
        return position
    }

    private fun isDelimiter(codePoint: Int): Boolean {
        for (delimiterCodePoint in delimiterCodePoints) {
            if (delimiterCodePoint == codePoint) {
                return true
            }
        }
        return false
    }

    /**
     * Tests if there are more tokens available from this tokenizer's string.
     * If this method returns `true`, then a subsequent call to
     * `nextToken` with no argument will successfully return a token.
     *
     * @return  `true` if and only if there is at least one token
     * in the string after the current position; `false`
     * otherwise.
     */
    fun hasMoreTokens(): Boolean {
        /*
         * Temporarily store this position and use it in the following
         * nextToken() method only if the delimiters haven't been changed in
         * that nextToken() invocation.
         */
        newPosition = skipDelimiters(currentPosition)
        return (newPosition < maxPosition)
    }

    /**
     * Returns the next token from this string tokenizer.
     *
     * @return     the next token from this string tokenizer.
     * @throws     NoSuchElementException  if there are no more tokens in this
     * tokenizer's string.
     */
    fun nextToken(): String {
        /*
         * If next position already computed in hasMoreElements() and
         * delimiters have changed between the computation and this invocation,
         * then use the computed value.
         */

        currentPosition = if ((newPosition >= 0 && !delimsChanged)) newPosition else skipDelimiters(
            currentPosition
        )

        /* Reset these anyway */
        delimsChanged = false
        newPosition = -1

        if (currentPosition >= maxPosition) throw NoSuchElementException()
        val start = currentPosition
        currentPosition = scanToken(currentPosition)
        return str.substring(start, currentPosition)
    }

    /**
     * Returns the next token in this string tokenizer's string. First,
     * the set of characters considered to be delimiters by this
     * `StringTokenizer` object is changed to be the characters in
     * the string `delim`. Then the next token in the string
     * after the current position is returned. The current position is
     * advanced beyond the recognized token.  The new delimiter set
     * remains the default after this call.
     *
     * @param      delim   the new delimiters.
     * @return     the next token, after switching to the new delimiter set.
     * @throws     NoSuchElementException  if there are no more tokens in this
     * tokenizer's string.
     * @throws    NullPointerException if delim is `null`
     */
    fun nextToken(delim: String?): String {
        delimiters = delim

        /* delimiter string specified, so set the appropriate flag. */
        delimsChanged = true

        setMaxDelimCodePoint()
        return nextToken()
    }

    /**
     * Returns the same value as the `hasMoreTokens`
     * method. It exists so that this class can implement the
     * `Enumeration` interface.
     *
     * @return  `true` if there are more tokens;
     * `false` otherwise.
     * @see java.util.Enumeration
     *
     * @see java.util.StringTokenizer.hasMoreTokens
     */
    fun hasMoreElements(): Boolean {
        return hasMoreTokens()
    }

    /**
     * Returns the same value as the `nextToken` method,
     * except that its declared return value is `Object` rather than
     * `String`. It exists so that this class can implement the
     * `Enumeration` interface.
     *
     * @return     the next token in the string.
     * @throws     NoSuchElementException  if there are no more tokens in this
     * tokenizer's string.
     * @see java.util.Enumeration
     *
     * @see java.util.StringTokenizer.nextToken
     */
    fun nextElement(): Any {
        return nextToken()
    }

    /**
     * Calculates the number of times that this tokenizer's
     * `nextToken` method can be called before it generates an
     * exception. The current position is not advanced.
     *
     * @return  the number of tokens remaining in the string using the current
     * delimiter set.
     * @see java.util.StringTokenizer.nextToken
     */
    fun countTokens(): Int {
        var count = 0
        var currpos = currentPosition
        while (currpos < maxPosition) {
            currpos = skipDelimiters(currpos)
            if (currpos >= maxPosition) break
            currpos = scanToken(currpos)
            count++
        }
        return count
    }
}
